I try to use crash utility for opening kernel crash dump.
The system have 6 GB memory. Almost all memory are free.
I already try kernel-default, kernel-vanilla, kernel-debug-default. 
Kernel version 5.0.2.

Gdb cannot open crash dump.

crash dump in attach... Ops it`s too big. I can sent by email.

Log:
linux-bvg0:/var/crash/2019-03-22-11:32 # ls
dmesg.txt  README.txt  System.map-5.0.2-1-debug  vmcore 
vmlinux-5.0.2-1-debug.gz
linux-bvg0:/var/crash/2019-03-22-11:32 # crash ./vmlinux-5.0.2-1-debug.gz
./vmcore 

crash 7.2.3
Copyright (C) 2002-2017  Red Hat, Inc.
Copyright (C) 2004, 2005, 2006, 2010  IBM Corporation
Copyright (C) 1999-2006  Hewlett-Packard Co
Copyright (C) 2005, 2006, 2011, 2012  Fujitsu Limited
Copyright (C) 2006, 2007  VA Linux Systems Japan K.K.
Copyright (C) 2005, 2011  NEC Corporation
Copyright (C) 1999, 2002, 2007  Silicon Graphics, Inc.
Copyright (C) 1999, 2000, 2001, 2002  Mission Critical Linux, Inc.
This program is free software, covered by the GNU General Public License,
and you are welcome to change it and/or distribute copies of it under
certain conditions.  Enter "help copying" to see the conditions.
This program has absolutely no warranty.  Enter "help warranty" for details.

GNU gdb (GDB) 7.6                                         
Copyright (C) 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-unknown-linux-gnu"...

WARNING: kernel relocated [240MB]: patching 94647 gdb minimal_symbol values

please wait... (gathering module symbol data)   buf_1K_used: 2498      
   buf_2K_used: 1
   buf_4K_used: 1
   buf_8K_used: 0
  buf_32K_used: 0
    buf_1K_ovf: 0
    buf_2K_ovf: 0
    buf_4K_ovf: 0
    buf_8K_ovf: 0
   buf_32K_ovf: 0
 buf_1K_maxuse:  2 of 10
 buf_2K_maxuse:  1 of 10
 buf_4K_maxuse:  1 of 5
 buf_8K_maxuse:  0 of 5
buf_32K_maxuse:  0 of 1
  buf_inuse[5]: [3][0][0][0][0]
      smallest: 8
       largest: 373662157340
      embedded: 3
  max_embedded: 3
       mallocs: 1
         frees: 1
    reqs/total: 2502/373662353699
  average size: 149345465

crash: cannot allocate any more memory!

linux-bvg0:/var/crash/2019-03-22-11:32 # uname -r
5.0.2-1-vanilla